package com.spzx.product.service.impl;

import com.baomidou.mybatisplus.annotation.TableName;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.spzx.product.api.vo.SkuLockVo;
import com.spzx.product.domain.SkuStock;
import com.spzx.product.mapper.SkuStockMapper;
import com.spzx.product.service.SkuStockService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.spzx.product.vo.SkuStockVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.CollectionUtils;

import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

/**
 * <p>
 * 商品sku库存表 服务实现类
 * </p>
 *
 * @author lynn
 * @since 2025-03-12
 */
@Service
public class SkuStockServiceImpl extends ServiceImpl<SkuStockMapper, SkuStock> implements SkuStockService {
    @Autowired
    private RedisTemplate redisTemplate;


    @Override
    public SkuStockVo getSkuStock(Long skuId) {
        // 根据skuId查询商品库存
        LambdaQueryWrapper<SkuStock> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper
                .eq(SkuStock::getSkuId, skuId)
                .select(SkuStock::getAvailableNum, SkuStock::getSaleNum);
        SkuStock skuStock = baseMapper.selectOne(queryWrapper);
        // 封装数据
        SkuStockVo skuStockVo = new SkuStockVo();
        skuStockVo.setAvailableNum(skuStock.getAvailableNum());
        skuStockVo.setSaleNum(skuStock.getSaleNum());
        skuStockVo.setSkuId(skuId);
        return skuStockVo;
    }

    @Transactional(rollbackFor = {Exception.class})
    @Override
    public String checkAndLock(String orderNo, List<SkuLockVo> skuLockVoList) {

        // 遍历所有商品，验库存并锁库存
        skuLockVoList.forEach(skuLockVo -> {
            // 验库存：查询，返回是当前sku的库存信息
            SkuStock skuStock = baseMapper.check(skuLockVo.getSkuId(), skuLockVo.getSkuNum());
            // 如果是null，这里就验库存失败
            if (null == skuStock) {
                skuLockVo.setHaveStock(false);//没有足够库存
            } else {
                skuLockVo.setHaveStock(true);//有足够库存
            }
        });

        // 只要有一个商品库存不足
        if (skuLockVoList.stream().anyMatch(skuLockVo -> !skuLockVo.isHaveStock())) {

            // 过滤出所有库存不足的商品
            List<SkuLockVo> noStockList = skuLockVoList
                    .stream()
                    .filter(item -> !item.isHaveStock())
                    .toList();

            //组装错误提示
            StringBuffer errorMsg = new StringBuffer();
            for (SkuLockVo skuLockVo : noStockList) {

                //查询现有库存
                Integer num = baseMapper.selectById(skuLockVo.getSkuId()).getAvailableNum();
                errorMsg
                        .append(skuLockVo.getSkuName())
                        .append("库存不足，剩余库存：")
                        .append(num)
                        .append("；");
            }

            //返回错误信息
            return errorMsg.toString();

        } else {//所有商品库存充足

            for (SkuLockVo skuLockVo : skuLockVoList) {
                //锁定库存
                baseMapper.lock(skuLockVo.getSkuId(), skuLockVo.getSkuNum());
            }
        }

        // 如果所有商品都锁定成功的情况下，需要缓存锁定信息到redis。以方便将来解锁库存 或者 减库存
        String dataKey = "sku:lock:data:" + orderNo;
        redisTemplate.opsForValue().set(dataKey, skuLockVoList);
        return "";
    }

    @Transactional(rollbackFor = {Exception.class})
    @Override
    public void unlock(String orderNo) {

        //幂等性处理
        String key = "sku:unlock:" + orderNo;
        Boolean isFirst = redisTemplate.opsForValue().setIfAbsent(key, orderNo, 1, TimeUnit.MINUTES);
        if(!isFirst) return;

        // 获取锁定库存的缓存信息
        String dataKey = "sku:lock:data:" + orderNo;
        List<SkuLockVo> skuLockVoList = (List<SkuLockVo>)redisTemplate.opsForValue().get(dataKey);
        if(!CollectionUtils.isEmpty(skuLockVoList)){
            // 解锁库存
            for (SkuLockVo skuLockVo : skuLockVoList) {
                baseMapper.unlock(skuLockVo.getSkuId(), skuLockVo.getSkuNum());
            }
        }

        // 解锁库存之后，删除锁定库存的缓存
        redisTemplate.delete(dataKey);
    }

    /**
     * 扣减库存
     * @param orderNo
     */
    @Override
    public void minus(String orderNo) {
        //幂等性判断
        String key = "sku:minus" + orderNo;
        Boolean isFirst = redisTemplate.opsForValue().setIfAbsent(key, orderNo, 1, TimeUnit.MINUTES);
        if(!isFirst){
            return;
        }
        //获取锁定库存的缓存信息
        String dataKey = "sku:lock:data:" + orderNo;
        List<SkuLockVo> skuLockVoList = (List<SkuLockVo>)redisTemplate.opsForValue().get(dataKey);
        if(!CollectionUtils.isEmpty(skuLockVoList)){
            //减库存
            for (SkuLockVo skuLockVo : skuLockVoList) {
                baseMapper.minus(skuLockVo.getSkuId(), skuLockVo.getSkuNum());
            }
        }
        //扣减库存之后，删除锁定库存的缓存
        redisTemplate.delete(dataKey);
    }
}
